Abstract

An epidermal growth factor receptor (EGFR) mutation is the best marker of sensitivity to the EGFR tyrosine kinase inhibitors gefitinib and erlotinib. Polymerase chain reaction (PCR)-based methods combined with the use of fluorescence probes, such as the Scorpion Amplification Refractory Mutation System (ARMS) or the PCR-Invader method, are frequently used to detect EGFR mutations before therapy. The sensitivities and specificities of these methods are satisfactory; however, there is potential to further improve the cost and detection time. We developed a new method for the rapid and reliable detection of EGFR mutations by using a combination of mutation-specific primers and the newly developed ultra-rapid real-time PCR (Hyper-PCR) amplification method that can be accomplished in <7 min. We designed specific ARMS primers for the common EGFR del E746-A750 mutations, and optimized the reaction conditions for the PCR machine that contained a thin disc-type reaction vessel, the temperature of which could be quickly altered by rotating it on thermal sources. We used Hyper-PCR to analyze the common EGFR mutations del E746-A750 and L858R in lung cancer samples from 143 non-small cell lung cancer (NSCLC) patients. The results were compared with those obtained by direct sequencing, conventional PCR, and the PCR-Invader method. Using the direct sequencing method, 13 (9.1%) and 15 (10.5%) NSCLC samples were positive for the del E746-A750 and L858R mutations, respectively, while the Hyper-PCR method revealed that 15 (10.5%) and 18 (12.6%) samples were positive for the del E746-A750 and L858R mutations, respectively. Five samples, whose results were discordant between the Hyper-PCR and direct sequencing methods, were analyzed by conventional PCR and the PCR-Invader method, and the results were found to be consistent with those obtained by Hyper-PCR. These results suggest that the novel Hyper-PCR method is an inexpensive, rapid, and reliable diagnostic test for EGFR mutations.